391 research outputs found

    In-Vitro Evaluation of Antagonistic Trichoderma Strains for Eradicating Phellinus Noxius In Colonised Wood

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    [EN] The aim of the present in vitro studies was to identify Trichoderma strains from Hong Kong with highly antagonistic potential against the basidiomycete Phellinus noxius (Corner) G. Cunn. Dual culture and interaction tests using samples of balsa wood (Ochroma lagopus Sw.), as well as studies on fungal growth at different temperatures and water activities, were conducted. The impact of Trichoderma strains on wood colonisation and decomposition by three P. noxius isolates were quantitatively analysed by measuring dry weight loss and the rate of eradication of the pathogen from the test wood. Most Trichoderma strains revealed antagonistic potential against P. noxius in these in vitro studies. In the wood blocks incubat-ed with P. noxius and then treated with Trichoderma T-TMS1 for 24 weeks, 100% eradica-tion of three P. noxius isolates was recorded. The results indicate that the application of Trichoderma strains may be a promising and environmentally benign method of eradicating P. noxius from wood debris in soils.We thank Muni Arborist Limited for assisting in the preparation of wood materials, use of facilities and support. Financial and technical support for project WQ/054/12 provided by The Chinese University of Hong Kong and Tree Management Office of the Development Bureau (Works Branch) of Hong Kong Government is gratefully acknowledged.Ribera Regal, J.; Tang, A.; Schubert, M.; Lam, R.; Chu, L.; Leung, M.; Kwan, H.... (2016). In-Vitro Evaluation of Antagonistic Trichoderma Strains for Eradicating Phellinus Noxius In Colonised Wood. Journal of Tropical Forest Science. 28(4):457-468. http://hdl.handle.net/10251/150303S45746828

    Study protocol for "Moving bright, eating smart"- a phase 2 clinical trial on the acceptability and feasibility of a diet and physical activity intervention to prevent recurrence in colorectal cancer survivors

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    Background: Colorectal cancer is the second most common cancer and cancer-killer in Hong Kong with an alarming increasing incidence in recent years. The latest World Cancer Research Fund report concluded that foods low in fibre, and high in red and processed meat cause colorectal cancer whereas physical activity protects againstcolon cancer. Yet, the influence of these lifestyle factors on cancer outcome is largely unknown even though cancer survivors are eager for lifestyle modifications. Observational studies suggested that low intake of a Western-pattern diet and high physical activity level reduced colorectal cancer mortality. The Theory of PlannedBehaviour and the Health Action Process Approach have guided the design of intervention models targeting a wide range of health-related behaviours.Methods/design: We aim to demonstrate the feasibility of two behavioural interventions intended to improve colorectal cancer outcome and which are designed to increase physical activity level and reduce consumption of a Western-pattern diet. This three year study will be a multicentre, randomised controlled trial in a 2x2 factorialdesign comparing the “Moving Bright, Eating Smart” (physical activity and diet) programme against usual care. Subjects will be recruited over a 12-month period, undertake intervention for 12 months and followed up for a further 12 months. Baseline, interim and three post-intervention assessments will be conducted. Two hundred and twenty-two colorectal cancer patients who completed curative treatment without evidence of recurrence will be recruited into the study. Primary outcome measure will be whether physical activity and dietary targets are met at the end of the 12-month intervention. Secondary outcome measures include the magnitude andmechanism of behavioural change, the degree and determinants of compliance, and the additional health benefits and side effects of the intervention.Discussion: The results of this study will establish the feasibility of targeting the two behaviours (diet and physical activity) and demonstrate the magnitude of behaviour change. The information will facilitate the design of a further larger phase III randomised controlled trial with colorectal cancer outcome as the study endpoint to determine whether this intervention model would reduce colorectal cancer recurrence and mortality

    Constraints on Large Extra Dimensions with Bulk Neutrinos

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    We consider right-handed neutrinos propagating in δ\delta (large) extra dimensions, whose only coupling to Standard Model fields is the Yukawa coupling to the left-handed neutrino and the Higgs boson. These theories are attractive as they can explain the smallness of the neutrino mass, as has already been shown. We show that if δ\delta is bigger than two, there are strong constraints on the radius of the extra dimensions, resulting from the experimental limit on the probability of an active state to mix into the large number of sterile Kaluza-Klein states of the bulk neutrino. We also calculate the bounds on the radius resulting from requiring that perturbative unitarity be valid in the theory, in an imagined Higgs-Higgs scattering channel.Comment: 24 pages, 4 figures, revtex4. v2: Minor typos corrected, references adde

    Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes

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    © 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations.Peer reviewe

    Search for single top quarks in the tau+jets channel using 4.8 fb1^{-1} of ppˉp\bar{p} collision data

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    We present the first direct search for single top quark production using tau leptons. The search is based on 4.8 fb1^{-1} of integrated luminosity collected in ppˉp\bar{p} collisions at s\sqrt{s}=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. We select events with a final state including an isolated tau lepton, missing transverse energy, two or three jets, one or two of them bb tagged. We use a multivariate technique to discriminate signal from background. The number of events observed in data in this final state is consistent with the signal plus background expectation. We set in the tau+jets channel an upper limit on the single top quark cross section of \TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected sensitivity for the observation of single top production when combining it with electron+jets and muon+jets channels already published by the D0 collaboration with 2.3 fb1^{-1} of data. We measure a combined cross section of \SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure

    Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV

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    We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6 figure

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

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    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let

    Search for a scalar or vector particle decaying into Zgamma in ppbar collisions at sqrt(s) = 1.96 TeV

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    We present a search for a narrow scalar or vector resonance decaying into Zgamma with a subsequent Z decay into a pair of electrons or muons. The data for this search were collected with the D0 detector at the Fermilab Tevatron ppbar collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0) fb-1 of data, we observe 49 (50) candidate events in the electron (muon) channel, in good agreement with the standard model prediction. From the combination of both channels, we derive 95% C.L. upper limits on the cross section times branching fraction (sigma x B) into Zgamma. These limits range from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/c^2 to 2.5 (3.1) pb for a mass of 140 GeV/c^2.Comment: Published by Phys. Lett.

    Search for charged Higgs bosons in top quark decays

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    We present a search for charged Higgs bosons in top quark decays. We analyze the \eplus, \muplus, eeee, eμe\mu, μμ\mu\mu, \etau and \mutau final states from top quark pair production events, using data from about 1fb1{\text{fb}}^{-1} of integrated luminosity recorded by the \dzero experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a τ\tau lepton and a τ\tau neutrino and a third one where both decays appear. We extract limits on the branching ratio B(tH+b)B(t\to H^+ b) for all these models. We use two methods, one where the ttˉt\bar{t} production cross section is fixed, and one where the cross section is fitted simultaneously with B(tH+b)B(t\to H^+b). Based on the extracted limits, we exclude regions in the charged Higgs boson mass and tanβ\tan \beta parameter space for different scenarios of the minimal supersymmetric standard model.Comment: 10 pages, 8 figures, submitted to PL

    Search for the associated production of a b quark and a neutral supersymmetric Higgs boson which decays to tau pairs

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    We report results from a search for production of a neutral Higgs boson in association with a bb quark. We search for Higgs decays to τ\tau pairs with one τ\tau subsequently decaying to a muon and the other to hadrons. The data correspond to 2.7fb1^{-1} of \ppbar collisions recorded by the D0 detector at s=1.96\sqrt{s} = 1.96TeV. The data are found to be consistent with background predictions. The result allows us to exclude a significant region of parameter space of the minimal supersymmetric model.Comment: Submitted to Phys. Rev. Letter
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